#include <iostream>
#include <stdlib.h>

#include <glut.h>

using namespace std;

bool lightEnabled = true;

GLfloat	lightPosX			= -6;
bool	directionForward	= true;

//Called when a key is pressed
void handleKeypress(unsigned char key, int x, int y) 
{
	switch (key) 
	{
	case 'i':
		if(lightEnabled)
			glDisable(GL_LIGHTING);
		else
			glEnable(GL_LIGHTING);
		lightEnabled = !lightEnabled;
		break;
	case 27: //Escape key
		exit(0);
	}
}

//Initializes 3D rendering
void initRendering() 
{
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_COLOR_MATERIAL);
	glEnable(GL_LIGHTING); //Enable lighting
	glEnable(GL_LIGHT0); //Enable light #0
	glEnable(GL_LIGHT1); //Enable light #1
	glEnable(GL_LIGHT2); //Enable light #2
	glEnable(GL_NORMALIZE); //Automatically normalize normals
	//glShadeModel(GL_SMOOTH); //Enable smooth shading
}

//Called when the window is resized
void handleResize(int w, int h) 
{
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0, (double)w / (double)h, 1.0, 200.0);
}

float _angle = -70.0f;

//Draws the 3D scene
void Render() 
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	
	glTranslatef(0.0f, 0.0f, -8.0f);
	
	//Add ambient light
	GLfloat ambientColor[] = {0.2f, 0.2f, 0.2f, 1.0f}; //Color (0.2, 0.2, 0.2)
	glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientColor);
	
	//Add positioned light
	GLfloat lightColor0[] = {0.5f, 0.5f, 0.5f, 1.0f}; //Color (0.5, 0.5, 0.5)
	GLfloat lightPos0[] = {4.0f, 0.0f, 8.0f, 1.0f}; //Positioned at (4, 0, 8)
	glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColor0);
	glLightfv(GL_LIGHT0, GL_POSITION, lightPos0);
	
	//Add directed light
	GLfloat lightColor1[] = {0.5f, 0.2f, 0.2f, 1.0f}; //Color (0.5, 0.2, 0.2)
	//Coming from the direction (-1, 0.5, 0.5)
	GLfloat lightPos1[] = {-1.0f, 0.5f, 0.5f, 0.0f};
	glLightfv(GL_LIGHT1, GL_DIFFUSE, lightColor1);
	glLightfv(GL_LIGHT1, GL_POSITION, lightPos1);

	// Add ex light
	GLfloat lightColor2[]	= { 0.f, 1.f, 0.f, 1.f };
	GLfloat lightPos2[]		= { lightPosX, 0.5f, 0.5f, 0.f };
	glLightfv(GL_LIGHT2, GL_DIFFUSE, lightColor2);
	glLightfv(GL_LIGHT2, GL_POSITION, lightPos2);
	//
	
	glRotatef(_angle, 1.0f, 1.0f, 1.0f);
	glColor3f(1.0f, 1.0f, 0.0f);

	glutSolidTeapot(1.5);

	glutSwapBuffers();
}

void update(int value) {
	_angle += 1.5f;
	if (_angle > 360) {
		_angle -= 360;
	}

	if(lightPosX < -6 || lightPosX > 6)
		directionForward = !directionForward;

	if(directionForward)
		lightPosX += 0.2;
	else
		lightPosX -= 0.2;
	
	glutPostRedisplay();
	glutTimerFunc(25, update, 0);
}

int main(int argc, char** argv) {
	//Initialize GLUT
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(640, 640);
	
	//Create the window
	glutCreateWindow("Lighting");
	initRendering();
	
	//Set handler functions
	glutDisplayFunc(Render);
	glutKeyboardFunc(handleKeypress);
	glutReshapeFunc(handleResize);
	
	glutTimerFunc(25, update, 0); //Add a timer
	
	glutMainLoop();
	return 0;
}








 